How to Create a Scratch Disk for Adobe Photoshop

Add scratch space to improve Adobe Photoshop CS5 performance.

If you don't have enough RAM available for Adobe Photoshop CS5 to perform an operation or respond to a command, the application uses hard drive space as a proprietary form of supplemental memory. While Photoshop looks by default to your startup drive for scratch space, that's not the best place to send it in search of this form of virtual memory. Ideally, your computer has a partition or drive you can dedicate to serving this purpose, preferably not physically located on your start up drive at all. Choose the fastest drive you can assign, one that's not used for storing your working files.

Instructions

1. Launch Adobe Photoshop CS5. Click "Edit" then "Preferences."

2. Click on the "Scratch Disks" section of your Photoshop preferences. Click on the arrows to promote or demote your drives and partitions as scratch space.

3. Look for all drives or partitions with check marks in their "Active" check boxes. These are the drives or partitions currently assigned to serve as scratch space. If any of them contain your working files or are located on your startup drive, consider un-checking and deactivating them in favor of better choices. Check the "Active" box to add a drive or partition as scratch space.

4. Click on the "OK" button to accept your changes. Restart Photoshop to make them take effect. Change your scratch drive assignments again if and when you change your hardware configuration.

5. Press "F8" to open the "Info" panel if it isn't visible. While you're working in Photoshop, look at the "Efficiency" rating displayed in the "Info" panel, expressed as a percentage. An efficiency rating of 100 percent means that Photoshop isn't relying on scratch disk space to provide memory for your current file operations. If the number falls below this threshold, you're now using scratch space. If you consistently see low efficiency ratings, consider upgrading the amount of memory on your computer for better performance.

Tips & Warnings

• If you can devote a RAID to serve as scratch space, you'll benefit from the speed the RAID can offer in this capacity. Keep your scratch drive defragmented for best operation. If you routinely work with very large files, consider purchasing a drive to dedicate to scratch space.

• Don't try to add networked drives to your list of scratch drives. Photoshop accepts only local drives for this purpose.

References

• Adobe Systems: Using Adobe Photoshop CS5